Most automotive vehicles, especially passenger-type vehicles, have a trunk located in a rear region of the vehicle. The floor of the trunk typically has a sunken well for storage of a spare tire. With the exception of the sunken well, the floor of the trunk is typically covered with a blanket of sound insulation to prevent road noise from passing through the trunk region and into the passenger compartment via the rear seat of the vehicle. A carpet is installed on top of the sound insulation. The carpet usually covers the sunken well cap or door that encloses the spare tire, jack and wheel lug wrench. The tire stored in the sunken well may be a temporary small-size spare tire or a regular full-size spare tire. It is desirable to provide a trunk liner that essentially covers most of the trunk region of the vehicle and incorporates an enclosure door over the sunken well which stores the spare tire. It is desirable to provide a trunk liner that can be quickly assembled onto the trunk floor of an automotive vehicle. It is also desirable to provide an automotive vehicle trunk liner that will maintain its position within the trunk without the extensive use of fastening devices.